Effect of a Dietary Intervention on Intracellular Lipid Levels, Insulin Sensitivity, and Glycemic Control in Type 2 Diabetes

NCT ID: NCT04088981

Last Updated: 2025-06-27

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

WITHDRAWN

Clinical Phase

NA

Study Classification

INTERVENTIONAL

Study Start Date

2025-07-31

Study Completion Date

2026-07-31

Brief Summary

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The purpose of this study is to compare the effects of a low-fat, plant-based dietary intervention and a portion-controlled dietary intervention (compliant with current American Diabetes Association (ADA) guidelines) on changes in intramyocellular and hepatocellular lipid content in adults with type 2 diabetes. Changes in insulin sensitivity and glycemic control will also be assessed in this study. The study duration is 44 weeks.

Detailed Description

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Type 2 diabetes is a disease characterized by discordance between the amount of insulin produced by pancreatic β-cells and the amount of insulin required to overcome insulin resistance in the liver and peripheral tissues. The development of insulin resistance has been strongly associated with the prolonged accumulation of lipids (fats) in the liver cells ("hepatocellular lipid") and muscle cells ("intramyocellular lipid"). Conventional pharmacologic therapeutics for type 2 diabetes, like metformin, are designed to reduce the accumulation of hepatocellular and intramyocellular lipids and, thereby, augment insulin sensitivity. Research has shown that a low-fat, plant-based diet, in which the consumption of lipids is limited, is a similarly effective therapeutic intervention for the reduction of hepatocellular and intramyocellular lipid content and the improvement of insulin sensitivity in type 2 diabetes.

The purpose of this study is to compare the effects of low-fat, plant-based dietary intervention and a portion-controlled dietary intervention (compliant with current American Diabetes Association (ADA) guidelines) on hepatocellular and intramyocellular lipid content in adults with type 2 diabetes. Using a cross-over design, participants with type 2 diabetes will be randomly assigned to start with a plant-based or a portion-controlled diet for 22 weeks. The two groups will then switch to the opposite diet regimen for an additional 22 weeks. Before and after each intervention period, the investigators will measure intramuscular and liver fat content. The investigators will also assess the relationship between these variables, insulin sensitivity, and glycemic control.

The investigators hypothesize that both dietary interventions will result in reductions in intramuscular and liver fat content, and that these changes will be associated with improvements in insulin sensitivity and glycemic control in individuals with type 2 diabetes. The investigators further hypothesize that the low-fat, plant-based dietary intervention will elicit greater changes in intracellular lipid concentration, compared with the portion-controlled dietary intervention.

Conditions

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Diabetes Mellitus, Type 2

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

CROSSOVER

randomized, cross-over
Primary Study Purpose

TREATMENT

Blinding Strategy

SINGLE

Outcome Assessors

Study Groups

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Low-fat, vegan diet

For a 22-week period, participants will be asked to follow a low-fat vegan diet which consists of whole grains, vegetables, legumes, and fruits, with no restriction on energy intake. Animal products and added oils will be excluded. In choosing grain products and starchy vegetables (e.g., bread, potatoes), participants will be encouraged to select those retaining their natural fiber and having a glycemic index \<70, using tables standardized to a value of 100 for glucose.

Group Type ACTIVE_COMPARATOR

Dietary intervention

Intervention Type BEHAVIORAL

Low-fat, plant-based diet and a portion-controlled diet

Portion-controlled diet

For a 22-week period, participants will be asked to follow a portion-controlled diet which will include individualized diet plans that reduce daily energy intake by 500 kcal for overweight participants, and keep carbohydrate intake reasonably stable over time. It will derive 50% of total energy from carbohydrates, 20% from protein, and less than 30% from fat (≤7% saturated fat), with less than 200 mg/day of cholesterol/day.

Group Type ACTIVE_COMPARATOR

Dietary intervention

Intervention Type BEHAVIORAL

Low-fat, plant-based diet and a portion-controlled diet

Interventions

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Dietary intervention

Low-fat, plant-based diet and a portion-controlled diet

Intervention Type BEHAVIORAL

Eligibility Criteria

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Inclusion Criteria

1. Men and women with type 2 diabetes treated by diet and/or oral hypoglycemic agents other that sulfonylureas
2. Age ≥18 years
3. Body mass index 26-40 kg/m2
4. Medications (antidiabetic, antihypertensive, and lipid-lowering) have been stable for the past 3 months
5. HbA1c between 6-10.5% (42-88 mmol/mol)

Exclusion Criteria

1. Diabetes mellitus, type 1 and/or treatment with insulin or sulfonylureas
2. Metal implants, such as a cardiac pacemaker or an aneurysm clip
3. History of any endocrine condition that would affect body weight, such as thyroid disease, pituitary abnormality, or Cushing's syndrome
4. Smoking during the past six months
5. Alcohol consumption of more than 2 drinks per day or the equivalent, episodic increased drinking (e.g., more than 2 drinks per day on weekends), or a history of alcohol abuse or dependency followed by any current use
6. Use of recreational drugs in the past 6 months
7. Use within the preceding six months of medications that affect appetite or body weight, such as estrogens or other hormones, thyroid medications, systemic steroids, antidepressants (tricyclics, MAOIs, SSRIs), antipsychotics, lithium, anticonvulsants, appetite suppressants or other weight-loss drugs, herbs for weight loss or mood, St. John's wort, ephedra, beta blockers
8. Pregnancy or intention to become pregnant during the study period
9. Unstable medical or psychiatric illness
10. Evidence of an eating disorder
11. Likely to be disruptive in group sessions
12. Already following a low-fat, vegan diet
13. Lack of English fluency
14. Inability to maintain current medication regimen
15. Inability or unwillingness to participate in all components of the study
16. Intention to follow another weight-loss method during the trial

Participants will also review and complete the Yale MRI Safety Questionnaire to determine eligibility for the study.
Minimum Eligible Age

18 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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Yale University

OTHER

Sponsor Role collaborator

Physicians Committee for Responsible Medicine

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Principal Investigators

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Hana Kahleova, MD, PhD

Role: PRINCIPAL_INVESTIGATOR

Physicians Committee for Responsible Medicine

Locations

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Physicians Committee for Responsible Medicine

Washington D.C., District of Columbia, United States

Site Status

Countries

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United States

References

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Other Identifiers

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Pro00037991

Identifier Type: -

Identifier Source: org_study_id

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